Microbial Potentiometric Sensors (MPS) utilize endemic biofilms to generate a signal using a measurable potentiometric difference, without the use of cleaning, maintenance, and reagents of conventional sensor monitoring methods. These advantages are suitable for monitoring bioreactions in water distribution systems, soils, and wastewater treatment. In controlled fermentation processes, monitoring seeks to avoid contamination and degradation, which results in loss of productivity. MPS have yet to be applied to monitor the fermentation of milk to yogurt. This study examined the feasibility of using MPS technology to monitor the progress of milk fermentation in real-time with a bench-scale model bioreactor. Signal data obtained by the MPS was analyzed and assessed for the ability to model and predict the time of complete fermentation. Analysis of complete fermentation times in conjunction with pH and MPS signal values found characteristics indicative of complete fermentation. The method detection limit was assessed to inform of the method’s capacity to distinguish complete fermentation time. A sensitivity analysis was conducted to develop a more robust method for predicting complete fermentation time. At this proof-of-concept scale, MPS successfully performed in this capacity to monitor bioreaction conditions continuously. MPS captured information as fermentation progressed, was completed, and as the yogurt product naturally began to decay. Analysis of the data obtained with the technology found predictions of complete fermentation time within a two hour range, with further assessment in the sensitivity analysis narrowing this timeframe to less than 45 minutes. This study revealed the challenges in precisely predicting complete fermentation;however, advancement of a robust analytical method and demonstration of technical feasibility promotes further MPS technology applications that seek to monitor conditions in real-time to preserve health and production.

The current practice of municipal stormwater management in the United States has failed to effectively reduce the amount of pollutants discharged into surface waters. Water impairment as a result of polluted stormwater runoff from urbanized areas remains a significant concern despite federally mandated efforts to reduce the impact of these discharges. To begin addressing these shortfalls the Environmental Protection Agency contracted the National Research Council to investigate the extent of the stormwater program and to identify areas that require improvement in order to more effectively implement the program. Their findings indicated widespread, foundational flaws with the stormwater regulatory structure and proposed new permitting guidelines. The purpose of this study was to explore the specific shortcomings of stormwater management in the Maricopa County region and to suggest the establishment of a regional authority. Doing so would require an alternative permitting regime to replace the current approach of population based municipal permitting with a permit that considered the entire urbanized region. The organizational structure, legality concerns and intergovernmental partnerships needed to properly establish such a regional authority were part of this study. The effect of this approach suggested a more effective, efficient and economical model of municipal stormwater management that better addressed certain Integrated Urban Stormwater Management strategies and began to address the program weaknesses identified by the National Research Council.